Electrolytic interrupter



A1126, 1957 K. KORDESCH Em 2,802,157l

ELECTROLYTIC INTERRUPTER Filed 0G11. 19, 1954 KARL KORDESCH FR/ED/WCH KORNFE/L.

x ATTO'RNEY.

United States Patent C ELECTROLYTIC INTERRUPTER Karl Kordesch and Friedrich Kornfeil, Long Branch,

N. J., assignors to the United States of America as represented by the Secretary of the Army Application October 19, 1954, Serial No. 463,336

1 Claim. (Cl.`317-232) (Granted under Title 35, U. S. Code (1952), sec. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment of any royalty thereon.

This invention relates to electrolytic interrupters and more particularly to such interrupters wherein the concentration and volume of the electrolyte therein is maintained at a relatively constantvalue over a long period of operation.

The electrolytic interrupter art essentially comprises two basic systems, viz; the Wehnelt and Simon systems. The Wehnelt system. substantially includes a thin wire platinum cathode and aplatinum plate anode, the electrodes being immersed in a sulfuric acid electrolyte. In operation, the presence of a high current density on the platinum wire cathode causes a small portion of the electrolyte to evaporate therefrom resulting in the formation of a thin gas film on the surface of the platinum wire and a consequent interruption of the current ow. Upon recondensation of the gas iilm, electrical conductivity is restored in the system. If a constant atmospheric pressure is maintained in the system, the interruption takes place at a constant rate.

The structure and principle of operation of the Simon system are similar to that of the Wehnelt system with the ditference being that the zone of high current density is not located at the cathode but in a capillary located within the electrolyte. The presence of a high current density in the capillary results in the formation of a vapor pocket therein which causes an interruption in current ow.

During the operation of the above set forth known interrupters, the electrolyte is decomposed. As a result, the sulfuric acid (l) becomes more concentrated causing a change in its conductivity with consequent changes in current density and interrupting frequency and (2) the volume of the electrolyte decreases. Therefore, the overall period of continuous and constant operation of the interrupter is limited by the quantity of the electrolyte. Another characteristic of these interrupter systems is their incapability of operating at lower pressures thereby eliminating the possibility of decreasing the voltage necessary for operation since the formation of hydrogen and oxygen causes an increase in the pressure unless the system is permanently connected to suction.

lt is, accordingly, the primary object of the present invention to provide an electrolytic interrupter wherein the concentration and quantity of the electrolyte remains relatively constant for an appreciable period of operation.

It is a further objects to provide an electrolytic interrupter wherein there is provided means for effecting the recombination of the products of electrolysis produced in the operation thereof.

Another object is to provide an electrolytic interrupter which is operable at pressures lower than atmospheric pressure and at substantially reduced operating voltages.

In accordance with the present invention, there is provided an electrolytic interrupter comprising a chamber, an aqueous electrolyte contained therein, an anode and a cathode disposed within said electrolyte and a material 2,802,157 Patented Aug. 6, 1957 ICC within said chamber for catalyzing the combination of the hydrogen and oxygen products of electrolysis produced during interrupter operation to water.

For a better understanding of the invention, together with other and further objects thereof, reference is had to the following escription taken in connection with the accompanying drawings and its scope will be pointed out `in the appended claims.

In the drawing, in Fig. 1 there is shown an example of the Wehnelt type electrolytic interrupter;

Fig. 2 is an example of the Simon type interrupter;

Fig. 3 is an embodiment of the present invention applied to the Wehnelt system; and

Fig. 4 is an embodiment of the present invention as applied to the Simon system.

Referring new more particularly to Fig. 1, there is shown the conventional Wehnelt interrupter. An aqueous electrolyte 10 such as sulfuric acid is contained in a receptacle 12 which consists of a refractory insulating material such as ceramic. The concentration of electrolyte 10 may be predetermined as desired. Disposed within electrolyte 10 are a cathode 14 consisting of a thin platinum wire, about 0.1 inch in length and an anode consisting of a platinum plate 16 with leads 17 extending from anode 16 and cathode 14 for connection in an external circuit. Part of platinum wire cathode 14 is usually contained in an insulating chamber 1S substantially as shown and consisting of ceramic, glass and the like. A removable ceramic cover 20 for receptacle 12 is generally provided in this type of interrupter.

In operation, when a high current density is present on cathode 14, the electrolyte evaporates resulting in the formation of a thin gas film on the surface thereof and an interruption of the current in the interrupter. With the interruption of the current, the gas film is permitted to condense through cooling and conductivity is restored. The Wehnelt interrupter generally is operated at voltages of 70 to 90 volts and 6 or more amperes. The frequencies of interruption depend upon the inductances of the interrupted circuit.

Fig. 2 which shows the Simon interrupter is similar in construction to the Wehnelt device except that the cathode 22 is a platinum plate similar to anode 16. Anode 16 in the Simon device is disposed within an open glass or ceramic tube 24 which has an open capillary taper 26 about 0.02 inch in diameter at the end thereof, capillary 26 being immersed in electrolyte 10. The current interruption is efected by the formation of a gas pocket in capillary 26, the gas being caused by electrolyte evaporation due to high current density. The Simon device is usually operated at a voltage of to 200 volts and a current of 10 or more amperes.

Both the Wehnelt and Simon systems are generally operated at atmospheric pressure. Due to such pressure, high current densities are required for electrolyte evapora` tion and consequent necessary higher operating voltages. Also, during operation, the electrolyte is decomposed with the formation of hydrogen and oxygen causing a loss of water with a resulting decrease in electrolyte volume and a higher concentration of said electrolyte. The net effect is to limit the effective period of use of the interrupter. Furthermore, due to the formation of hydrogen and oxygen during operation, the comparatively high pressure of operation is further increased unless the interrupter is permanently connected to suction.

In Fig. 3 there is shown an embodiment of the present invention as applied to the Wehnelt type interrupter. The chamber 2.3 consisting of either a refractory or an insulating material is permanently enclosed and evacuated to a pressure lower than atmospheric, preferably about 50 to 70 mm. mercury. The cathode 30 consists of a plurality of metal wires such as platinum in a brush like arrangement, the anode 16 consists of a plate of metal such as platinum and there is included within the chamber a moderately electrically heated platinum wire coil 32 (heating means not shown). The electrolyte 10 is preferably an aqueous solution of sulfuric acid in a concentration of from 5 to 30%.

The operation of the device of Fig. 3 is substantially similarto the operation of the Wehnelt interrupter. In addition, platinum coil 32 serves to catalyze the reformation to water of the oxygen and hydrogen products of electrolysis during operation of the device, thus maintaining both the concentration of the acid in the electrolyte and the electrolyte volume relatively constant. Instead of using platinum wire coil 32 as a catalyst, the catalytic effect may also be accomplished by the use of catalysts with a large surface such as platinum or palladium black in which cases there is no need for heat. The platinum or palladium black may for convenience be disposed on the inner surface of chamber 28 by conventional methods well known in the art. The use of the greater number of platinum wires in cathode 30 results in much higher frequencies than in the conventional single wire cathode of the Wehnelt interrupter as alternating formation of gas on dierent discrete wires results in a much greater amount of current ow interruptions in a given period.

In Fig. 4, wherein there is shown an embodiment of the present invention as applied to the Simon type interrupter, there is provided the same moderately electrically heated platinum coil 32 or platinum or palladium black to catalyze the formation of hydrogen and oxygen to water within substantially evacuated chamber 28. The tube 34 surrounding anode 16 terminates at its submerged end in a plurality of open capillaries 36, the capillaries being about 0.04 inch in diameter. The device of Fig. 4 is operated lower than atmospheric pressure, preferably at a pressure of 50 to 70 mm. mercury at about 12 volts and 2 amperes. The multiplicity of capillaries 36 serves the same purpose as the many wires of the cathode in the device of Fig. 3. For example, using the operating parameters set forth and a tube 34 terminating in about 30 capillaries, the commonly required frequency of 400 regular interruptions per second is readily obtained when leads 17 are connected in a circuit including a primary of a transformer having a proper inductance value. The many capillaries in the submerged end of tube 34 is in effect equivalent to a perforated diaphragm.

While there have been described what are, at present, considered to be preferred embodiments of this invention, it will be obvious to those skilled in the art that various changes and modifications may be made without departing from the invention, and, it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

An electrolytic interrupter comprising a chamber evacuated to a pressure of from to 70 mm. mercury, an electrolyte consisting of an aqueous solution of sulfuric acid contained therein, an anode and a cathode immersed in said electrolyte, a tube surrounding said anode, at least one end of said tube being immersed in said electrolyte, said immersed end having a plurality of narrow width openings therethrough, said openings providing a plurality of locations for forming current interrupting gas pockets of evaporated electrolyte, and a material within said chamber for catalyzing the formation to water of the hydrogen and oxygen produced during the operation of said interrupter, said material being selected from the group consisting of platinum, platinum black and palladium black.

References Cited in the le of this patent Y UNITED STATES PATENTS 686,295 Heinze Nov. 12, 1901 1,020,698 Kelley Mar. 19, 1912 1,769,837 11u11 July 1, 1930 

